Fig. 1From: PDGFB-targeted functional MRI nanoswitch for activatable T1–T2 dual-modal ultra-sensitive diagnosis of cancera TEM image and b HRTEM image of Fe3O4. TEM images of c FS and d FMS. HAADF-STEM and elemental distribution images of e FS and f FMS. g XRD patterns of Fe3O4, FS, and FMS. h N2 adsorption/desorption isotherms of FS and FMS (inset: pore size distribution), i XPS full spectra of Fe3O4, FS, and FMSBack to article page